Scottish Conservative leader Ruth Davidson has asked Nicola Sturgeon if she feels "embarrassed, ashamed or both" about her government's performance on education.

The pair clashed at First Minister's Questions two days after a biannual survey showed less than half of S2 pupils can write well.

Trainee teachers also told a Holyrood committee on Wednesday they did not have the required numeracy skills "to be able to teach it to 11-year-olds at a reasonable standard".

In December, Scotland dropped down the PISA international league tables for reading and science and remained average for maths.

Davidson said: "Today in Scotland, in an S2 class of 30 pupils, on average five can't write properly. That's double the number just four years ago.

"When the First Minister sees statistics like these does she feel embarrassed, ashamed or both?"

She added: "We like to pride ourselves in Scotland that our education system was the best in the world and after ten years of this SNP government, we can do so no longer."

The SNP leader said the bi-annual survey asked S2 pupils if they could reach the standard expected of S3 pupils.

Sturgeon said: "What I feel is utterly determined - determined to carry on with the changes we're making in Scottish education so that we continue to see the improvements in attainment and progress in closing the attainment gap."

The First Minister added later: "We've got good performance across education in Scotland but there are areas where we have recognised that we need to do better and this government is getting on with the job of taking the action that will deliver these improvements."